Manufacturing method of a semiconductor device

ABSTRACT

A method of manufacturing a semiconductor device includes forming a first etch stop pattern on a lower structure including a first region and a second region to expose the second region, stacking a plurality of stack structures on the lower structure to overlap the second region and the first etch stop pattern, forming a stepped stack structure by etching the plurality of stack structures to expose an end portion of the first etch stop pattern, forming a slit passing through the stepped stack structure and the first etch stop pattern, and replacing sacrificial layers of the plurality of stack structures and the first etch stop pattern with conductive patterns through the slit.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. § 119(a) toKorean patent application number 10-2018-0065609 filed on Jun. 7, 2018in the Korean Intellectual Property Office, the entire disclosure ofwhich is incorporated herein by reference.

BACKGROUND 1. Technical Field

The present disclosure generally relates to a semiconductor device and amethod of manufacturing a semiconductor device, and more particularly,to a three-dimensional semiconductor device and a method ofmanufacturing a three-dimensional semiconductor device.

2. Related Art

A semiconductor device may include a memory device capable of storingdata. A three-dimensional semiconductor device has been proposed so asto improve integration density of the semiconductor device. Thethree-dimensional semiconductor device may include memory cells stackedon a substrate to be spaced apart from each other. The three-dimensionalsemiconductor device may include interlayer insulating layers,conductive patterns, a vertical channel passing through the interlayerinsulating layers and the conductive patterns, and a data storage layerarranged between each of the conductive patterns and the verticalchannel. The memory cells may be defined at intersections of thevertical channel and the conductive patterns.

To increase storage capacity of the three-dimensional semiconductordevice, a large number of conductive patterns and interlayer insulatinglayers may be stacked. Thereby, however, a level of difficulty of amanufacturing process may increase.

SUMMARY

In accordance with an embodiment, a method of manufacturing asemiconductor device may include forming a lower structure including afirst region and a second region, forming a first etch stop pattern onthe lower structure to expose the second region, stacking a plurality ofstack structures on the lower structure to overlap the second region andthe first etch stop pattern, forming a stepped stack structure byetching the plurality of stack structures to expose an end portion ofthe first etch stop pattern, forming a slit passing through the steppedstack structure and the first etch stop pattern, and replacingsacrificial layers of the plurality of stack structures and the firstetch stop pattern with conductive patterns through the slit.

In accordance with an embodiment, a method of manufacturing asemiconductor device may include forming a lower structure including afirst region and a second region; forming a first etch stop pattern onthe lower structure to expose the second region; forming a first stackstructure on the lower structure to overlap the second region and thefirst etch stop pattern; forming a second etch stop pattern on the firststack structure to expose the second region; forming a second stackstructure on the second etch stop pattern, the second stack structureoverlapping the first region and extending over the second region tooverlap the second region; forming a stepped stack structure by etchingthe second stack structure, the second etch stop pattern, and the firststack structure to expose an end portion of the first etch stop pattern;forming a slit passing through the stepped stack structure and the firstetch stop pattern; and replacing sacrificial layers of each of the firstand second stack structures, the first etch stop pattern, and the secondetch stop pattern with conductive patterns through the slit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically illustrating a semiconductordevice according to an embodiment of the present disclosure;

FIGS. 2A to 2C are diagrams illustrating a structure of a memory blockaccording to an embodiment of the present disclosure;

FIGS. 3A to 3D are cross-sectional views illustrating various structuresof a memory string according to embodiments of the present disclosure;

FIGS. 4A to 4C, 5A to 5F, 6A, 6B, and 7A to 7D are cross-sectional viewsillustrating a manufacturing method of a semiconductor device accordingto an embodiment of the present disclosure;

FIGS. 8A to 8E are cross-sectional views illustrating a manufacturingmethod of a semiconductor device according to an embodiment of thepresent disclosure;

FIGS. 9A to 9E are cross-sectional views illustrating a manufacturingmethod of a semiconductor device according to an embodiment of thepresent disclosure;

FIG. 10 is a block diagram illustrating a configuration of a memorysystem according to an embodiment of the present disclosure; and

FIG. 11 is a block diagram illustrating the configuration of a computingsystem according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The technical spirit of the present disclosure may be changed in variousmanners and may be implemented as embodiments having various aspects.Hereinafter, the present disclosure will be described by a limitednumber of possible embodiments so that those skilled in the art canimplement the present disclosure in practice.

Although the terms “first” and/or “second” are used herein to describevarious elements, the elements should not be limited by these terms. Theterms are only used to distinguish one element from another element, notto indicate a number or priority of elements. For instance, a firstelement discussed below could be termed a second element, and a secondelement could be termed a first element without departing from theteachings of the present disclosure.

When one element is referred to as being “coupled” or “connected” toanother element, the one element can be directly coupled or connected tothe other element or intervening elements may be present between the“coupled” or “connected” elements. In contrast, when an element isreferred to as being “directly coupled” or “directly connected” toanother element, there are no intervening elements present between the“directly coupled” or “directly connected” elements. Other expressionsthat explain a relationship between elements, such as “between,”“directly between,” “adjacent to,” or “directly adjacent to” should beconstrued in the same way.

When one element is referred to as being “on” another element, the oneelement can be directly on the other element or intervening elements maybe present between the one element and the other element. In contrast,when an element is referred to as being “directly on” another element,there are no intervening elements present between the element and theother element.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. In the presentdisclosure, singular forms are intended to include the plural forms aswell, unless the context clearly indicates otherwise. It will be furtherunderstood that the terms “comprise,” “include,” “have,” etc., when usedin this specification, specify the presence of stated features, numbers,steps, operations, elements, components, and/or combinations thereof butdo not preclude the presence or addition of one or more other features,numbers, steps, operations, elements, components, and/or combinationsthereof.

Embodiments of the present application are directed to a manufacturingmethod of a semiconductor device that may be capable of lowering a levelof difficulty of a manufacturing process of a three-dimensionalsemiconductor device.

FIG. 1 is a block diagram schematically illustrating a semiconductordevice according to an embodiment of the present disclosure.

Referring to FIG. 1, the semiconductor device according to an embodimentmay include a substrate SUB, a peripheral circuit structure PC disposedon the substrate SUB, and memory blocks BLK1 to BLKn disposed on theperipheral circuit structure PC.

The substrate SUB may be a single crystal semiconductor layer. Forexample, the substrate SUB may be a bulk silicon substrate, asilicon-on-insulator substrate, a germanium substrate, agermanium-on-insulator substrate, a silicon-germanium substrate, or anepitaxial thin film formed by a selective epitaxial growth method. Thesubstrate SUB may include a first region A1 and a second region A2. Thefirst region A1 of the substrate SUB may be overlapped with the memoryblocks BLK1 to BLKn. The second region A2 of the substrate SUB may notbe overlapped with each of the memory blocks BLK1 to BLKn.

The peripheral circuit structure PC may include a row decoder, a columndecoder, a page buffer, and a control circuit. The peripheral circuitstructure PC may include n-channel metal oxide semiconductor (NMOS)transistors and p-channel metal oxide semiconductor (PMOS) transistorselectrically coupled to the memory blocks BLK1 to BLKn, a resistor, anda capacitor. The peripheral circuit structure PC may be overlapped withat least one of the first region A1 and the second region A2 of thesubstrate SUB.

The memory blocks BLK1 to BLKn each may include a plurality of cellstrings electrically coupled to bit lines, impurity doping regions, wordlines, and select lines. The memory blocks BLK1 to BLKn may beoverlapped with the first region A1.

FIGS. 2A to 2C are diagrams illustrating a structure of a memory blockaccording to an embodiment of the present disclosure.

FIG. 2A is a perspective view illustrating a three-dimensionalarrangement of memory cells included in the memory block.

Referring to FIG. 2A, the memory block according to an embodiment mayinclude word lines WL parallel to a horizontal plane extending along afirst direction I and a second direction II. The first direction I mayintersect the second direction II. The word lines WL may be conductivepatterns coupled to gate electrodes of the memory cells. Each of theword lines WL may have a linear shape extending along the firstdirection I. The word lines WL neighboring each other in the seconddirection II on the same plane may be separated from each other by aslit SI. The word lines WL may be stacked to be spaced apart from eachother in a third direction III. The third direction III mayperpendicularly cross the horizontal plane extending along the firstdirection I and the second direction II. Each of the word lines WL mayenclose vertical channels VCH.

Each of the vertical channels VCH may extend in the third direction IIIto pass through the word lines WL. In order to increase arrangementdensity of the vertical channels VCH, the vertical channels VCH may bearranged in a zigzag format. However, an embodiment of the presentdisclosure may not be limited thereto. For example, the verticalchannels VCH may be arranged in a matrix format.

Each of multilayers ML including a data storage layer may be disposedbetween each of the vertical channels VCH and each of the word lines WL.The memory cells may be formed at intersections of the word lines WL andeach of the vertical channels VCH. Gate electrodes of a plurality ofmemory cells disposed on the same horizontal plane may be commonlycontrolled by one of the word lines WL. Each of the vertical channelsVCH may serve as a channel of a plurality of memory cells stacked in thethird direction III.

FIG. 2B is an enlarged cross-sectional view of the multilayer MLdisposed between each vertical channel VCH and each word line WL asillustrated in FIG. 2A.

Referring to FIG. 2B, the vertical channel VCH may be surrounded by themultilayer ML. The multilayer ML may be disposed between the verticalchannel VCH and the word line WL. The multilayer ML may include a tunnelinsulating layer TI enclosing the vertical channel VCH, a data storagelayer DL enclosing the tunnel insulating layer TI, and a blockinginsulating layer BI enclosing the data storage layer DL. The datastorage layer DL may store data changed using Fowler-Nordheim tunnelingcaused by a difference in voltage between the word line WL and thevertical channel VCH. For this operation, the data storage layer DL mayinclude various materials, for example, a nitride layer capable oftrapping charges. In addition, the data storage layer DL may includesilicon, a phase-change material, nanodots, etc. The blocking insulatinglayer BI may include an oxide layer capable of blocking charges. Thetunnel insulating layer TI may include a silicon oxide layer capable ofcharge tunneling.

The vertical channel VCH may include a semiconductor layer. For example,the vertical channel VCH may include a silicon layer. The verticalchannel VCH may have various structures. For example, the verticalchannel VCH may have a ring shape defining a core region COA. The coreregion COA may be completely filled with the vertical channel VCH. Inanother example, the core region COA may be filled with at least one ofan insulating layer and a doped semiconductor layer.

FIG. 2C is a cross-sectional view illustrating end portions of the wordlines WL illustrated in FIG. 2A.

Referring to FIG. 2C, the word lines WL may be stacked in the thirddirection III to form a step structure. In other words, the word linesWL may include a lower pattern and an upper pattern which form the stepstructure. The upper pattern may be defined as being disposed above thelower pattern. An end portion of the lower pattern may be longer thanthe upper pattern in the first direction I so as to be exposed withoutbeing overlapped by the upper pattern.

Each of the word lines WL may be divided into a line portion LP and apad portion PP. The pad portion PP may extend from an end portion of theline portion LP. The pad portion PP may have a greater thickness thanthe line portion LP in the third direction III. In other words, athickness D2 of the pad portion PP may be greater than a thickness D1 ofthe line portion LP. The pad portion PP may be exposed by the stepstructure of the word lines WL. An end portion of each of the word linesWL may protrude in the third direction III by the pad portion PP. Eachof word line contact plugs WCT may be coupled to the corresponding padportion PP to extend in the third direction III. The thick pad portionPP may prevent a phenomenon in which the word line contact plugs WCTpass through the word lines WL.

A memory string included in the memory block may include the structuresdescribed in FIGS. 2A to 2C. A memory string according to an embodimentof the present disclosure may be variously embodied.

FIGS. 3A to 3D are cross-sectional views illustrating various structuresof a memory string according to an embodiment of the present disclosure.

Referring to FIGS. 3A to 3D, memory strings MSR may each include memorycells stacked along each of the vertical channels VCH. The memory cellsmay be formed at intersections of the corresponding vertical channel VCHand the word lines WL. The vertical channels VCH may be coupled to adoped region SA disposed under the word lines WL as illustrated in FIGS.3A to 3C. Alternatively, the vertical channels VCH may be coupled to apipe channel PCH disposed under the word lines WL as illustrated in FIG.3D.

Referring to FIGS. 3A to 3C, each of the vertical channels VCH may passthrough a plurality of stack structures stacked on each other. UndercutsUC may be defined at boundaries between the plurality of stackstructures. The undercuts UC may be defined in a hole in which each ofthe vertical channels VCH is disposed. Among the plurality of stackstructures, a stack structure disposed at the lowermost layer may bedefined as a first stack structure STA1, and a stack structure disposedat the uppermost layer may be defined as a second stack structure STA2.The second stack structure STA2 may be covered by an upper insulatinglayer UIL. The vertical channels VCH may extend to pass through theupper insulating layer UIL.

The plurality of stack structures may be divided into two groupsincluding the first stack structure STA1 and the second stack structureSTA2, respectively. The present disclosure is not limited thereto, andthe plurality of stack structures may further include one or more stackstructures disposed between the first stack structure STA1 and thesecond stack structure STA2 as well as the first stack structure STA1and the second stack structure STA2.

Each of the plurality of stack structures may include interlayerinsulating layers ILD and conductive patterns CP which are alternatelystacked. Each interlayer insulating layer ILD may include an insulatingmaterial such as a silicon oxide layer. Each conductive pattern CP mayinclude various conductive materials such as a doped silicon layer, ametal layer, a metal silicide layer, a barrier layer, and the like, andmay include two or more types of conductive materials. The interlayerinsulating layers ILD and the conductive patterns CP may be penetratedby the slit SI.

The slit SI may be filled with a sidewall insulating layer SWI and asource contact structure SC as illustrated in FIG. 3A, or may be filledwith a slit insulating layer SIL as illustrated in FIGS. 3B and 3C.

Referring to FIGS. 3A and 3B, the conductive patterns CP may serve as asource select line SSL, the word lines WL, and a drain select line DSL.For example, the uppermost conductive pattern of the second stackstructure STA2 may serve as the drain select line DSL, the lowermostconductive pattern of the first stack structure STA1 may serve as thesource select line SSL. The conductive patterns CP between the sourceselect line SSL and the drain select line DSL may serve as the wordlines WL described with reference to FIGS. 2A to 2C. The conductivepattern which serves as the drain select line DSL is not limited to theuppermost conductive pattern of the second stack structure STA2. Forexample, each of the one or more conductive patterns successivelydisposed under the uppermost conductive pattern of the second stackstructure STA2 may serve as the drain select line DSL. The conductivepattern which serves as the source select line SSL is not limited to thelowermost conductive pattern of the first stack structure STA1. Forexample, each of the one or more conductive patterns successivelydisposed above the lowermost conductive pattern of the first stackstructure STA1 may serve as the source select line SSL.

Each of the vertical channels VCH may include a semiconductor layer. Forexample, each of the vertical channels VCH may include a silicon layer.The vertical channels VCH may directly contact the doped region SA. Thedoped region SA may include a source dopant. For example, the dopedregion SA may be a doped silicon layer including an n type dopant.

Referring to FIG. 3A, the doped region SA may be coupled to a sidewallof each of the vertical channels VCH. For example, the doped region SAmay be disposed under the first stack structure STA1. The doped regionSA may have a structure in which first, second, and third dopedsemiconductor layers SA1, SA2, and SA3 are stacked. The first, second,and third doped semiconductor layers SA1, SA2, and SA3 may includedifferent conductivity type dopants, respectively or the sameconductivity type dopant. For example, each of the first, second, andthird doped semiconductor layers SA1, SA2, and SA3 may include an n typesilicon layer including an n type dopant. The third doped semiconductorlayer SA3 disposed between the first doped semiconductor layer SA1 andthe second doped semiconductor layer SA2 may directly contact sidewallsof the vertical channels VCH.

Each of the vertical channels VCH may pass through the second dopedsemiconductor layer SA2 and the third doped semiconductor layer SA3 toextend into the first doped semiconductor layer SA1. The multilayer MLillustrated in FIG. 2B may extend along an outer wall of each of thevertical channels VCH illustrated in FIG. 3A, and may be divided into anupper pattern MLa and a lower pattern MLb by the third dopedsemiconductor layer SA3.

The sidewall insulating layer SWI may be formed on a sidewall of theslit SI. The slit SI and the sidewall insulating layer SWI may furtherpass through the third doped semiconductor layer SA3. The source contactstructure SC in the slit SI may be insulated from the conductivepatterns CP by the sidewall insulating layer SWI. The source contactstructure SC may contact the doped region SA. For example, the sourcecontact structure SC may pass through the second doped semiconductorlayer SA2 and the third doped semiconductor layer SA3 to contact thefirst doped semiconductor layer SA1. The source contact structure SC mayinclude various conductive materials such as a doped silicon layer, ametal layer, a metal silicide layer, a barrier layer, and the like, andmay include two or more types of conductive materials. For example, thesource contact structure SC may have a stack structure of a dopedsilicon layer contacting the first doped semiconductor layer SA1 and ametal layer formed on the doped silicon layer. The doped silicon layermay include an n type dopant and the metal layer may include alow-resistance metal such as tungsten to lower resistance. A core regionof each of the vertical channels VCH may be filled with a coreinsulating layer CO and a doped semiconductor pattern CAP. The dopedsemiconductor pattern CAP may serve as a drain junction.

Referring to FIG. 3B, the doped region SA may be coupled to a bottomsurface of each of the vertical channels VCH. For example, the dopedregion SA may be disposed under the first stack structure STA1 andinclude an n type silicon layer including an n type dopant.

Each of the vertical channels VCH may extend along a top surface of thedoped region SA. The multilayer ML illustrated in FIG. 2B may extendalong a sidewall of each of the vertical channels VCH illustrated inFIG. 3B, and each of the vertical channels VCH may pass through themultilayer ML to contact the doped region SA.

A core region of each of the vertical channels VCH may be filled withthe core insulating layer CO and the doped semiconductor pattern CAP.The doped semiconductor pattern CAP may serve as a drain junction.

Referring to FIG. 3C, a lower stack structure LST may be disposedbetween the first stack structure STA1 and the doped region SA. Thelower stack structure LST may include a lower insulating layer LIL andthe source select line SSL which are alternately stacked. The sourceselect line SSL may be disposed at a single layer or at each of two ormore layers.

Referring to FIG. 3C, the conductive patterns CP included in the firstand second stack structures STA1 and STA2 may serve as the word lines WLand the drain select line DSL. A conductive pattern which is the same asthe conductive pattern as described with reference to FIGS. 3A and 3Bmay serve as the drain select line DSL. The conductive patterns CPdisposed between the drain select line DSL and the source select lineSSL may serve as the word lines WL.

The lower stack structure LST may be penetrated by lower channels LPC.The lower channels LPC may be aligned under the vertical channels VCH,respectively, and may be coupled to the vertical channels VCH,respectively. The lower channels LPC may be formed by a growth methodusing an epitaxial process and the like, or by a deposition method. Thelower channels LPC may directly contact the doped region SA. Each of thevertical channels VCH may be electrically coupled to the doped region SAvia the corresponding lower channel LPC. Each of the lower channels LPCmay serve as a channel layer of a source select transistor coupled tothe source select line SSL. Each of the lower channels LPC may besurrounded by a gate insulating layer GI. Each of the lower channels LPCmay be a doped silicon layer to which an impurity is doped. Each of thelower channels LPC may include an n type dopant.

The multilayer ML having a structure as illustrated in FIG. 2B mayextend along a sidewall of each of the vertical channels VCH and encloseeach of the vertical channels VCH. Each of the vertical channels VCH maypass through the multilayer ML to directly contact the correspondinglower channel LPC. A core region of each of the vertical channels VCHmay be filled with the core insulating layer CO and the dopedsemiconductor pattern CAP. The core insulating layer CO may be disposedbetween the corresponding lower channel LPC and the doped semiconductorpattern CAP, and the doped semiconductor pattern CAP may serve as adrain junction.

According to a structure illustrated in FIGS. 3A to 3C, the memorystring MSR may include memory cells and a drain select transistor whichare coupled in series along each of the vertical channels VCH. Thememory cells may be formed at intersections of each of the verticalchannels VCH and the word lines WL, and the drain select transistor maybe formed at an intersection of each of the vertical channels VCH andthe drain select line DSL.

The memory string MSR may further include a source select transistorcoupled in series to the memory cells. The source select transistor maybe formed at an intersection of each of the vertical channels VCH andthe source select line SSL under the memory cells as illustrated inFIGS. 3A and 3B, or at an intersection of each of the lower channels LPCand the source select line SSL under the memory cells as illustrated inFIG. 3C.

Referring to FIG. 3D, the memory string MSR may be defined along thepipe channel PCH and at least two vertical channels VCH1 and VCH2coupled to the pipe channel PCH. Hereinafter, for convenience ofexplanation, an example in which the memory string MSR includes thefirst vertical channel VCH1 and the second vertical channel VCH2 whichare coupled to the pipe channel PCH to be defined as a U type will bedescribed.

The first vertical channel VCH1 may pass through a drain side stackstructure STAD and the second vertical channel VCH2 may pass through asource side stack structure STAS. The drain side stack structure STADand the source side stack structure STAS may be the same layers anddisposed at the same level to each other. The drain side stack structureSTAD may be spaced apart from the source side stack structure STAS bythe slit SI and the silt insulating layer SIL filling the slit SI.

The drain side stack structure STAD and the source side stack structureSTAS may include a plurality of stack structures stacked thereon,respectively. The undercut UC may be defined between each of theboundaries of the plurality of stack structures. The undercut UC may bedefined in a hole in which each of the first and second verticalchannels VCH1 and VCH2 is disposed.

Each of the plurality of stack structures may include the interlayerinsulating layers ILD and the conductive patterns CP which arealternately stacked. The interlayer insulating layers ILD and theconductive patterns CP may include materials which are the same as thematerials as described with reference to FIGS. 3A to 3C. As defined inFIGS. 3A to 3C, among the plurality of stack structures, the stackstructure disposed at the lowermost layer may be defined as the firststack structure STA1, and the stack structure disposed at the uppermostlayer may be defined as the second stack structure STA2.

The second stack structure STA2 may be covered by the upper insulatinglayer UIL. Each of the first and second vertical channels VCH1 and VCH2may extend to pass through the upper insulating layer UIL.

The conductive patterns CP of the drain side stack structure STAD mayserve as the drain select line DSL and drain side word lines WLD. Theconductive patterns CP of the source side stack structure STAS may serveas the source select line SSL and source side word lines WLS.

The drain select line DSL may be the uppermost conductive pattern of thesecond stack structure STA2 which constitutes the drain side stackstructure STAD. In another example, the uppermost conductive pattern andeach of the one or more conductive patterns successively disposed underthe uppermost conductive pattern may further serve as the drain selectline DSL. The drain side word lines WLD may be the conductive patternsdisposed under the drain select line DSL.

The source select line SSL may be the uppermost conductive pattern ofthe second stack structure STA2 which constitutes the source side stackstructure STAS. In another example, the uppermost conductive pattern andeach of the one or more conductive patterns successively disposed underthe uppermost conductive pattern may serve as the source select lineSSL. The source side word lines WLS may be the conductive patternsdisposed under the source select line SSL.

The pipe channel PCH may be embedded in a pipe gate PG disposed underthe drain side stack structure STAD and the source side stack structureSTAS. The pipe gate PG may include various conductive materials. Forexample, the pipe gate PG may include doped silicon layers stacked as amultilayer. The pipe gate PG may extend to overlap the slit SI and theslit insulating layer SIL.

The pipe channel PCH may be integrated with the first vertical channelVCH1 and the second vertical channel VCH2 and serve as a channel of thememory string MSR. A channel layer including the pipe channel PCH, thefirst vertical channel VCH1, and the second vertical channel VCH2 mayinclude a semiconductor layer such as silicon.

The multilayer ML may extend along an outer wall of the channel layerincluding the pipe channel PCH, the first vertical channel VCH1, and thesecond vertical channel VCH2. The multilayer ML may include materiallayers which are the same as the material layers as described withreference to FIG. 2B. Core regions of each of the pipe channel PCH, thefirst vertical channel VCH1, and the second vertical channel VCH2 may befilled with the core insulating layer CO. The core insulating layer COmay have a lower height than the first vertical channel VCH1 and thesecond vertical channel VCH2. First and second doped semiconductorpatterns CAP1 and CAP2 may be disposed on opposite ends of the coreinsulating layer CO, respectively. The first doped semiconductor patternCAP1 may be surrounded by the first vertical channel VCH1 and serve as adrain junction. The second doped semiconductor pattern CAP2 may besurrounded by the second vertical channel VCH2 and serve as a sourcejunction.

Each of the first and second doped semiconductor patterns CAP1 and CAP2may include a doped silicon layer.

According to the structure illustrated in FIG. 3D, a drain selecttransistor may be formed at an intersection of the first verticalchannel VCH1 and the drain select line DSL, and drain side memory cellsmay be formed at intersections of the first vertical channel VCH1 andthe drain side word lines WLD. The drain side memory cells and the drainselect transistor may be coupled in series by the first vertical channelVCH1.

In addition, a source select transistor may be formed at an intersectionof the second vertical channel VCH2 and the source select line SSL, andsource side memory cells may be formed at intersections of the secondvertical channel VCH2 and the source side word lines WLS. The sourceside memory cells and the source select transistor may be coupled inseries by the second vertical channel VCH2.

The source side memory cells and the drain side memory cells may becoupled in series by a pipe transistor formed at an intersection of thepipe channel PCH and the pipe gate PG.

As a result, the memory string MSR illustrated in FIG. 3D may includethe drain select transistor, the drain side memory cells, the pipetransistor, the source side memory cells, and the source selecttransistor coupled in series by the channel layer including the pipechannel PCH, the first vertical channel VCH1, and the second verticalchannel VCH2.

In order to increase integration density of the memory string MSRdescribed with reference to FIGS. 3A to 3D, the number of memory cellsto be stacked may be increased. Hereinafter, various manufacturingmethods of a semiconductor device by which stability of a process may beincreased and a level of difficulty of the process may be decreased evenif the number of memory cells to be stacked is increased will bedescribed.

FIGS. 4A to 4C, 5A to 5F, 6A, 6B, and 7A to 7D are cross-sectional viewsillustrating a manufacturing method of a semiconductor device accordingto an embodiment of the present disclosure.

FIGS. 4A to 4C are cross-sectional views illustrating processes offorming a lower etch stop structure.

Referring to FIG. 4A, a first etch stop pattern 103 may be formed on alower structure 101 including the first region A1 and the second regionA2. The lower structure 101 may include the substrate SUB and theperipheral circuit structure PC which are illustrated in FIG. 1. Thelower structure 101 may further include various structures depending ona structure of a memory string to be formed. For example, the lowerstructure 101 may further include the doped region SA illustrated inFIG. 3B, the lower stack structure LST illustrated in FIG. 3C, or thepipe gate illustrated in FIG. 3D. An insulating layer may be disposed atthe uppermost layer of the lower structure 101.

The first region A1 and the second region A2 of the lower structure 101may correspond to the first region A1 and the second region A2 which areillustrated in FIG. 1. The first region A1 of the lower structure 101may be divided into a cell array region CA and a contact region CTA. Thecell array region CA may be overlapped by the vertical channels VCHillustrated in FIG. 2A and the contact region CTA may be overlapped bythe pad portions PP illustrated in FIG. 2C. The second region A2 of thelower structure 101 may not be overlapped by the word lines WL, thedrain select line DSL, and the source select line SSL which areillustrated in FIGS. 3A to 3D.

The first etch stop pattern 103 may include a material layer having adifferent etch rate from material layers which constitute a plurality ofstack structures to be formed later. The first etch stop pattern 103 mayinclude a material layer having a significantly different etch rate fromthe stack structures so as to decrease a slope of an etched surface of ahole or a slit during subsequent processes for forming the hole or theslit which pass through the stack structures. For example, the firstetch stop pattern 103 may include a material layer having asignificantly different etch rate from an oxide layer and a nitridelayer than a polysilicon layer. Considering these etch rates, the firstetch stop pattern 103 may include metal. For example, the first etchstop pattern 103 may include a titanium (Ti) compound, for example, atitanium nitride (TiN) layer.

The first etch stop pattern 103 may be formed to cover the first regionA1 of the lower structure 101 and expose the second region A2 of thelower structure 101. According to embodiments of the present disclosure,the first etch stop pattern 103 including metal may not remain in thesecond region A2 and the first etch stop pattern 103 may be formedbefore forming a stepped stack structure. Thereby, even if a contactplug (not illustrated) is disposed at the second region A2, a phenomenonin which the contact plug disposed at the second region A2 iselectrically coupled to the first etch stop pattern 103 to cause adefect in a semiconductor device may be prevented.

Subsequently, an insulating layer 105 may be formed to cover the firstetch stop pattern 103 and the second region A2 of the lower structure101. The insulating layer 105 may include an oxide layer.

Referring to FIG. 4B, to planarize a surface of the insulating layer 105shown in FIG. 4A, a planarizing process such as Chemical MechanicalPolishing (CMP) may be performed. Thereby, a surface of the first etchstop pattern 103 may be exposed, and an insulating pattern 105P coveringthe second region A2 and having a flat surface may be formed.

Referring to FIG. 4C, an insulating layer 107 covering the first etchstop pattern 103 and the insulating pattern 105P may be furtherdeposited. The insulating layer 107 may include an oxide layer. Theinsulating pattern 105P and the insulating layer 107 may serve as firstinterlayer insulating layers 109. The first interlayer insulating layer109 may cover the first etch stop pattern 103 and the second region A2of the lower structure 101 and may have a flat surface.

Through the processes as described in FIGS. 4A to 4C, a lower etch stopstructure ES including the first etch stop pattern 103 and the firstinterlayer insulating layer 109 may be formed on the lower structure101.

FIGS. 5A to 5F are cross-sectional views illustrating processes offorming a plurality of stack structures penetrated by a vertical channelon the lower etch stop structure ES.

Referring to FIG. 5A, a first stack structure MS1 may be formed on thelower etch stop structure ES. The first stack structure MS1 may beformed by alternately stacking first sacrificial layers 111 and firstinterlayer insulating layers 113 on the lower etch stop structure ES.The first sacrificial layers 111 and the first interlayer insulatinglayers 113 may extend to overlap the first etch stop pattern 103 and thesecond region A2. The first sacrificial layers 111 and the firstinterlayer insulating layers 113 may include different materials.

The first interlayer insulating layers 113 may insulate conductivepatterns from each other, and may have a high etch resistance withrespect to an etching material during an etching process for selectivelyremoving the first sacrificial layers 111. For example, the firstinterlayer insulating layers 113 may include oxide layers such as asilicon oxide layer and the first sacrificial layers 111 may includenitride layers such as a silicon nitride layer.

Subsequently, a first hole H1 passing through the first stack structureMS1 on the cell array region CA may be formed. The first hole H1 mayextend to further pass through the first etch stop pattern 103. A widthof a lower end of the first hole H1 may be increased using a differencein etch rate between the first etch stop pattern 103, and the firstinterlayer insulating layers 113 and the first sacrificial layers 111 ofthe first stack structure MS1. Thereby, a difference in width between anupper end and the lower end of the first hole H1 may be decreased. Sincethe first etch stop pattern 103 includes metal, the first etch stoppattern 103 may have a high etch resistance with respect to an etchingmaterial which etches the first stack structure MS1. Thereby, a level ofdifficulty of an etching process for forming the first hole H1 may belowered and the etching process may stably proceed.

Referring to FIG. 5B, a sacrificial pillar 120 may be formed in thefirst hole H1. Processes for forming the sacrificial pillar 120 mayinclude forming a protective oxide layer 115 on a surface of the firsthole H1, forming a metal layer 117 filling a portion of the first holeH1 on the protective oxide layer 115, and forming a second etch stoppattern 119 filling an upper portion of the first hole H1 on the metallayer 117. The metal layer 117 may include metal having strength capableof withstanding process stress, for example, tungsten (W). The secondetch stop pattern 119 may include the same material as the first etchstop pattern 103.

Referring to FIG. 5C, a second stack structure MS2 may be formed on thefirst stack structure MS1 so as to cover the sacrificial pillar 120. Thesecond stack structure MS2 may be formed by alternately stacking secondsacrificial layers 131 and second interlayer insulating layers 133 onthe first stack structure MS1. The second sacrificial layers 131 and thesecond interlayer insulating layers 133 may extend to overlap the firstetch stop pattern 103 and the second region A2. The second sacrificiallayers 131 may include the same material as the first sacrificial layers111, and the second interlayer insulating layers 133 may include thesame material as the first interlayer insulating layers 113.

Subsequently, a mask layer 135 may be formed on the second stackstructure MS2. The mask layer 135 may include a nitride layer such as asilicon nitride layer.

Referring to FIG. 5D, a mask pattern 135P may be formed by patterningthe mask layer 135 illustrated in FIG. 5C by using a photolithographyprocess. Thereafter, a second hole H2 exposing the second etch stoppattern 119 may be formed by etching the second stack structure MS2exposed by the mask pattern 135P.

During an etching process for forming the second hole H2, the secondetch stop pattern 119 may serve as an etch stop layer. A width of alower end of the second hole H2 may be increased using a difference inetch rate between the second etch stop pattern 119, and the secondinterlayer insulating layers 133 and the second sacrificial layers 131of the second stack structure MS2. Thereby, a difference in widthbetween an upper end and the lower end of the second hole H2 may bedecreased. Since the second etch stop pattern 119 includes metal, thesecond etch stop pattern 119 may have a high etch resistance withrespect to an etching material which etches the second stack structureMS2. Thereby, a level of difficulty of an etching process for formingthe second hole H2 may be lowered and the etching process may stablyproceed.

Referring to FIG. 5E, the first hole H1 may be opened by removing thesacrificial pillar through the second hole H2. Thereby, the first holeH1 and the second hole H2 may be coupled to each other to define achannel hole CH.

Referring to FIG. 5F, a multilayer 141 may be formed on a surface of thechannel hole CH. The multilayer 141 may have a structure consistent withembodiments described with reference to FIG. 2B. Thereafter, a channellayer 143 may be formed on the multilayer 141. The channel layer 143 mayserve as a vertical channel layer. The channel layer 143 may include asemiconductor layer. Thereafter, a core insulating layer 145 and a dopedsemiconductor pattern 147 filling a central region of the channel holeCH may be formed on the channel layer 143. The doped semiconductorpattern 147 may fill the central region of the channel hole CH on thecore insulating layer 145.

Although FIGS. 5A to 5F illustrate an embodiment in which the channellayer 143 passing through the first stack structure MS1 and the secondstack structure MS2 is formed, embodiments of the present disclosure arenot limited thereto. For example, one or more stack structures may befurther disposed between the first stack structure MS1 and the secondstack structure MS2.

FIGS. 6A and 6B are cross-sectional views illustrating processes offorming a stepped stack structure and processes of forming sacrificialpad patterns.

Referring to FIG. 6A, the second stack structure MS2 and the first stackstructure MS1 may be patterned (e.g. etched) to have stepped endportions SWS disposed on the contact region CTA. After forming thestepped end portions SWS, the mask pattern 135P illustrated in FIG. 5Fmay be removed.

The stepped end portions SWS may expose an end portion of the first etchstop pattern 103. The stepped end portions SWS may be defined as endportions of the first sacrificial layers 111 of the first stackstructure MS1 and end portions of the second sacrificial layers 131 ofthe second stack structure MS2. When the first stack structure MS1 andthe second stack structure MS2 are patterned (e.g. etched) to form thestepped stack structure, the first stack structure MS1 and the secondstack structure MS2 may be removed from the second region A2. In anembodiment, removal (e.g. by etching) of the first stack structure MS1and the second structure MS2 from the second region A2 may expose thesecond region A2. In an embodiment, removal (e.g. by etching) of thefirst stack structure MS1, the second structure MS2, and the insulatinglayer 107 from the second region A2 may expose the insulating pattern105P over the second region A2.

Referring to FIG. 6B, sacrificial pad patterns 151 may be formed on theend portion of the first etch stop pattern 103 which is exposed by thestepped stack structure and on the end portions of the first sacrificiallayers 111 and the end portions of the second sacrificial layers 131which are patterned to have the step shape.

Processes for forming the sacrificial pad patterns 151 may includeforming a sacrificial pad layer deposited on the first etch stop pattern103 exposed by the stepped stack structure, the first sacrificial layers111, and the second sacrificial layers 131 and etching a portion of thesacrificial pad layer. The sacrificial pad layer may include the samenitride layer as the first and second sacrificial layers 111 and 131.The sacrificial layer may be etched by a wet etching process usingphosphoric acid, and the sacrificial layer may be divided into theplurality of sacrificial pad patterns 151 through the etching process ofthe sacrificial pad layer.

The first etch stop pattern 103, which includes a material having a highetch resistance with respect to the etching process for forming thesacrificial pad patterns 151 as described above, may protect a structuredisposed under the first etch stop pattern 103 during the etchingprocess for forming the sacrificial pad patterns 151.

Subsequently, an upper insulating layer 155 covering the sacrificial padpatterns 151 and the stepped stack structure may be formed. A surface ofthe upper insulating layer 155 may be planarized.

FIGS. 7A to 7D are cross-sectional views illustrating replacementprocesses through a slit.

Referring to FIG. 7A, a first slit SI1 passing through the first stackstructure MS1 and the second stack structure MS2 on the cell arrayregion CA may be formed. The first slit SI1 may further pass through theupper insulating layer 155. The first etch stop pattern 103 of the loweretch stop structure ES may serve as an etch stop layer during the firstetching process for forming the first slit SIL. In an embodiment, thefirst slit SI1 may also further pass through the insulating layer 107 ofthe lower etch stop structure ES. A difference in width between a lowerend of the first slit SI1 and an upper end of the first slit SI1 may bedecreased using a large difference in etch rate between material layersof the first stack structure MS1 and the second stack structure MS2which are etched during the first etching process, and the first etchstop pattern 103 including metal.

Referring to FIG. 7B, a second slit SI2 may be formed by etching thefirst etch stop pattern, exposed by the first slit SI1, by the secondetching process. Thereby, the slit SI including the first slit SI1 andthe second slit SI2 may be defined.

Subsequently, a first horizontal opening HOP1 may be formed byselectively removing the first etch stop pattern through the slit SI.

Referring to FIG. 7C, the first sacrificial layers of the first stackstructure and the second sacrificial layers of the second stackstructure may be selectively removed through the slit SI. Regions fromwhich the first sacrificial layers of the first stack structure areremoved may be defined as second horizontal openings HOP2 and regionsfrom which the second sacrificial layers of the second stack structureare removed may be defined as third horizontal openings HOP3. When thefirst and second sacrificial layers are removed, sacrificial padpatterns including the same material as the first and second sacrificiallayers may be removed. Regions from which the sacrificial pad patternsare removed may be divided into first, second, and third verticalopenings VOP1, VOP2, and VOP3.

The first vertical opening VOP1 may be coupled to an end portion of thefirst horizontal opening HOP1 on the contact region CTA; the secondvertical openings VOP2 may be coupled to end portions of the secondhorizontal openings HOP2 on the contact region CTA, respectively; andthe third vertical openings VOP3 may be coupled to end portions of thethird horizontal openings HOP3 on the contact region CTA, respectively.

Referring to FIG. 7D, after filling the first, second, and thirdvertical openings VOP1, VOP2, and VOP3 and the first, second, and thirdhorizontal openings HOP1, HOP2, and HOP3 illustrated in FIG. 7C withconductive materials, the conductive patterns may be divided into aplurality of conductive patterns CP through the slit SI.

Each of the conductive patterns CP may include at least one of a dopedsilicon layer, a metal silicide layer, and a metal layer. Alow-resistance metal such as tungsten may be used for each of theconductive patterns CP for low resistance wiring. Each of the conductivepatterns CP may further include a barrier layer such as a titaniumnitride layer, a tungsten nitride layer, a tantalum nitride layer, andthe like. Each of the conductive patterns CP may include the lineportion LP extending from the cell array region CA to the contact regionCTA and the pad portion PP extending from an end portion of the lineportion LP and having a greater thickness than the line portion LP.

The conductive patterns CP may correspond to the conductive patterns CPshown in FIGS. 3A to 3D.

The above-described manufacturing method of the semiconductor deviceaccording to an embodiment of the present disclosure may be used to formthe memory string illustrated in FIGS. 3A to 3D.

FIGS. 8A to 8E are cross-sectional views illustrating a manufacturingmethod of a semiconductor device according to an embodiment of thepresent disclosure. For example, FIGS. 8A to 8E may be cross-sectionalviews illustrating a method for forming the memory string illustrated inFIG. 3A. Hereinafter, a detailed description of any repetitive processesdescribed above will be omitted.

Referring to FIG. 8A, a lower structure 201 including the first regionA1 and the second region A2 is formed. The lower structure 201 mayinclude a stack structure of a first doped semiconductor layer 281, afirst protective layer 283, a source sacrificial layer 285, a secondprotective layer 287, a second doped semiconductor layer 289 and aninterlayer insulating layer 291. The first doped semiconductor layer 281and the second doped semiconductor layer 289 may include doped siliconlayers. The first protective layer 283 and the second protective layer287 may include oxide layers. The source sacrificial layer 285 mayinclude an undoped semiconductor layer, for example, an undoped siliconlayer.

The first doped semiconductor layer 281, the first protective layer 283,the source sacrificial layer 285, the second protective layer 287, andthe second doped semiconductor layer 289 may be penetrated by isolationlayer 290.

The lower etch stop structure ES may be formed on the lower structure201 illustrated in FIG. 8A using the processes described with referenceto FIGS. 4A to 4C.

Thereafter, the first stack structure MS1 may be formed on the loweretch stop structure ES by a process which is the same as the processdescribed with reference to FIG. 5A. Subsequently, a first hole H1′passing through the first stack structure MS1 may be formed. The firsthole H1′ may further pass through the interlayer insulating layer 291,the second doped semiconductor layer 289, the second protective layer287, the source sacrificial layer 285, and the first protective layer283 disposed under the lower etch stop structure ES at the cell arrayregion CA to extend into the first doped semiconductor layer 281.

Referring to FIG. 8B, a plurality of stack structures penetrated by achannel hole CH′ may be formed and a multilayer 241 and a channel layer243 may be formed on a surface of the channel hole CH′ by using theprocesses described with reference to FIGS. 5D to 5F. Thereafter, a coreinsulating layer 245 and a doped semiconductor pattern 247 which aredisposed on the channel layer 243 and filling a central region of thechannel hole CH′ may be formed.

Each of the channel hole CH′, the core insulating layer 245, the channellayer 243, and the multilayer 241 may pass through the second dopedsemiconductor layer 289, the second protective layer 287, the sourcesacrificial layer 285, and the first protective layer 283 to extend intothe first doped semiconductor layer 281.

Subsequently, a stepped stack structure having a stepped end portion maybe formed on the contact region CTA and sacrificial pad patterns 251 maybe formed on the stepped end portion and an end portion of a first etchstop pattern 203 by using the processes described with reference toFIGS. 6A and 6B. The stepped end portion may be defined by end portionsof first sacrificial layers 211 of the stack structure MS1 and endportions of second sacrificial layers 231 of the second stack structureMS2. Subsequently, an upper insulating layer 255 may be formed.

Thereafter, a slit SI′ may be formed using the processes described withreference to FIGS. 7A and 7B. The slit SI′ may pass through the upperinsulating layer 255, the second stack structure MS2, the first stackstructure MS1, and the lower etch stop structure ES. In additionthereto, the slit SI′ may pass through the interlayer insulating layer291 and the second doped semiconductor layer 289 to expose the secondprotective layer 287.

Referring to FIG. 8C, the second protective layer exposed by the slitSI′ may be etched to expose the source sacrificial layer, and,subsequently, the source sacrificial layer may be removed. Themultilayer enclosing a portion of a sidewall of the channel layer 243may be exposed through a region from which the source sacrificial layeris removed. A horizontal opening HSP may be formed by removing theexposed multilayer. The multilayer may be divided into an upper pattern241 a and a lower pattern 241 b and the sidewall of the channel layer243 may be exposed by the horizontal opening HSP. When the horizontalopening HSP is formed, the first and second protective layers may beremoved to expose the first doped semiconductor layer 281 and the seconddoped semiconductor layer 289.

Referring to FIG. 8D, a third doped semiconductor layer 295 may beformed in the horizontal opening HSP illustrated in FIG. 8C. The thirddoped semiconductor layer 295 may contact the channel layer 243, thefirst doped semiconductor layer 281, and the second doped semiconductorlayer 289. The third doped semiconductor layer 295 may be formed by achemical vapor deposition method or a growth method using the channellayer 243, the first doped semiconductor layer 281, and the second dopedsemiconductor layer 289 as seed layers.

Referring to FIG. 8E, the first and second sacrificial layers, the firstetch stop pattern, and the sacrificial pad patterns may be replaced withthe conductive patterns CP by using the processes described with respectto FIGS. 7A to 7D.

Subsequently, the sidewall insulating layer SWI may be formed on asidewall of the slit SI′. Thereafter, the source contact structure SCfilling the slit SI′ may be formed. The source contact structure SC maypass through the sidewall insulating layer SWI to contact the firstdoped semiconductor layer 281.

Thereafter, contact plugs CT contacting the conductive patterns CP bypassing through the upper insulating layer 255 may be formed.

FIGS. 9A to 9E are cross-sectional views illustrating a manufacturingmethod of a semiconductor device according to an embodiment of thepresent disclosure. Hereinafter, a detailed description of anyrepetitive processes described above will be omitted.

Referring to FIG. 9A, a lower etch stop structure ES1 may be formed on alower structure 301 including the first region A1 and the second regionA2.

The lower structure 301 may include the substrate SUB and the peripheralcircuit structure PC which are illustrated in FIG. 1. The lowerstructure 301 may further include various structures depending on astructure of a memory string to be formed. For example, the lowerstructure 301 may include the first doped semiconductor layer 281, thefirst protective layer 283, the source sacrificial layer 285, the secondprotective layer 287, the second doped semiconductor layer 289, and theinterlayer insulating layer 291 which are described with reference toFIG. 8A. Alternatively, the lower structure 301 may further include thedoped region SA described with reference to FIG. 3B, the lower stackstructure LST described with reference to FIG. 3C, or the pipe gate PGdescribed with reference to FIG. 3D.

The lower etch stop structure ES1 may be formed using the processesdescribed with reference to FIGS. 4A to 4C.

Subsequently, the first stack structure MS1 may be formed on the loweretch stop structure ES1 by using the process described with reference toFIG. 5A. Thereafter, a first hole H1″ passing through the first stackstructure MS1 may be formed, and a protective oxide layer 315 may beformed on a surface of the first hole H1″. Subsequently, a metal layer317 filling a portion of the first hole H1″ may be formed on theprotective oxide layer 315. The metal layer 317 may include metal havingstrength to withstand process stress, for example, tungsten (W).

Thereafter, a second etch stop pattern 319 filling the first hole H1″ onthe metal layer 317 and extending to cover the first stack structure MS1may be formed. The second etch stop pattern 319 may be patterned not tooverlap the second region A2. The second etch stop pattern 319 mayinclude a first portion 319A filling the first hole H1″ and a secondportion 319B extending to cover the first stack structure MS1 on thefirst portion 319A. Processes for forming the second etch stop pattern319 may include forming the first portion 319A filling the first holeH″, forming an etch stop layer to cover the first portion 319A and thefirst stack structure MS1, and forming the second portion 319B bypatterning the etch stop layer.

The first portion 319A and the second portion 319B of the second etchstop pattern 319 may include the same material layer. The first portion319A and the second portion 319B of the second etch stop pattern 319 mayinclude the same material as a first etch stop pattern 303 of the loweretch stop structure ES1. The first and second etch stop patterns 303 and319 may be selected considering etch rates of material layers whichconstitute the first stack structure MS1 and the second stack structureMS2.

The first and second etch stop patterns 303 and 319 may include materiallayers having a significantly different etch rate from an oxide layerand a nitride layer than a polysilicon layer so as to decrease a slopeof an etched surface of the channel hole or the slit as described withreference to FIG. 4A. In other words, the first and second etch stoppatterns 303 and 319 may include metal. For example, the first andsecond etch stop patterns 303 and 319 may include a titanium (Ti)compound, such as a titanium nitride (TiN) layer.

The first and second etch stop patterns 303 and 319 may be patterned tocover the first region A1 of the lower structure 301 and expose thesecond region A2 of the lower structure 301 so that a phenomenon inwhich a contact plug disposed at the second region A2 is electricallycoupled to the first and second etch stop patterns 303 and 319 to causea defect in a semiconductor element may be prevented as described withreference to FIG. 4A.

The second etch stop pattern 319 may be covered by an interlayerinsulating layer 329. The interlayer insulating layer 329 may include afirst insulating layer 323 and a second insulating layer 325. The firstinsulating layer 323 may be formed using a process which is the same asthe process for forming the insulating pattern 105P as described withreference to FIGS. 4A and 4B. The second insulating layer 325 may beformed using a process which is the same as the process for forming theinsulating layer 107 as described with reference to FIG. 4C.Hereinafter, a stack structure of the second portion 319B of the secondetch stop pattern 319 and the interlayer insulating layer 329 may bedefined as an interlayer etch stop structure ES2.

After forming the interlayer etch stop structure ES2, the second stackstructure MS2 may be formed on the interlayer etch stop structure ES2 byusing the process described with reference to FIG. 5C. The second stackstructure MS2 may extend to overlap the first and second etch stoppatterns 303 and 319 and the second region A2.

Subsequently, a mask layer 335 may be formed on the second stackstructure MS2. The mask layer 335 may include a nitride layer such as asilicon nitride layer.

Referring to FIG. 9B, the mask layer 335 illustrated in FIG. 9A may bepatterned using a photolithography process. Thereby, a mask pattern 335Pmay be formed. Thereafter, a second hole H2″ exposing the first portion319A of the second etch stop pattern 319 may be formed by etching thesecond stack structure MS2 and the interlayer etch stop structure ES2which are exposed through the mask pattern 335P.

During an etching process for forming the second hole H2″, the secondetch stop pattern 319 may serve as an etch stop layer. A width of alower end of the second hole H2″ may be increased using a difference inetch rate between the second etch stop pattern 319, and secondinterlayer insulating layers 333 and second sacrificial layers 331 ofthe second stack structure MS2. Thereby, a difference in width betweenan upper end of the second hole H2″ and the lower end of the second holeH2″ may be decreased. The second hole H2″ may be aligned on the firsthole H1″.

Referring to FIG. 9C, the first hole H1″ may be opened by removing thefirst portion 319A of the second etch stop pattern 319, the metal layer317, and the protective oxide layer 315 through the second hole H2″illustrated in FIG. 9B. Thereby, the channel hole CH in which the firsthole H1″ and the second hole H2″ are coupled may be defined.

Thereafter, a multilayer 341, a channel layer 343, a core insulatinglayer 345, and a doped semiconductor pattern 347 may be formed in thechannel hole CH by using the process described with reference to FIG.5F.

Subsequently, a stepped stack structure having a stepped end portion maybe formed on the contact region CTA, and sacrificial pad patterns 351may be formed using the processes described with reference to FIGS. 6Aand 6B. In an embodiment, the processes to form the stepped stackstructure may also include etching the interlayer insulating layer (329of FIG. 9A) covering the second portion 319B of the second etch stoppattern 319; the etching of the interlayer insulating layer (329 of FIG.9A) may expose an end portion of the second portion 319B of the secondetch stop pattern 319. The stepped end portion may be defined by endportions of the second sacrificial layers 331 of the second stackstructure MS2, end portions of first sacrificial layers 311 of the firststack structure MS1, and an end portion of the second portion 319B ofthe second etch stop pattern 319. The sacrificial pad patterns 351 maybe formed on an end portion of the first etch stop pattern 303 and theend portions of the first sacrificial layers 311, the second portion319B of the second etch stop pattern 319, and the second sacrificiallayers 331 which define the stepped end portion, respectively.Thereafter, an upper insulating layer 355 may be formed.

Thereafter, a first slit SI1″ passing through the upper insulating layer355 and the second stack structure MS2 and exposing the second portion319B of the second etch stop pattern 319 may be formed. During the firstetching process for forming the first slit SI1″, the second portion 319Bof the second etch stop pattern 319 may serve as an etch stop layer. Inan embodiment, the first slit SI1″ may further pass through the secondinsulating layer (325 of FIG. 9A) of the interlayer insulating layer(329 of FIG. 9A).

Etching the second portion 319B of the second etch stop pattern 319which is exposed by the first slit SI1″ illustrated in FIG. 9C, etchingthe first stack structure MS1, and etching the first etch stop pattern303 may be sequentially performed. Thereby, a second slit SI2″ coupledto the first slit SI1″ and extending to pass through the lower structure301 may be formed as illustrated in FIG. 9D. Hereinafter, a connectionstructure of the first slit SI1″ and the second slit SI2″ may be definedas a slit SI″.

Referring to FIG. 9D, the lower structure 301, the first etch stoppattern 303, interlayer insulating layers 307, 313, and 333, the secondportion 319B of the second etch stop pattern 319, and the first andsecond sacrificial layers 311 and 331 may be exposed by a sidewall ofthe slit SI″. In an embodiment, the second insulating layer 325 of theinterlayer insulating layer (329 of FIG. 9A) may be also exposed by thesidewall of the slit SI″.

Subsequently, the first etch stop pattern 303 and the second portion319B of the second etch stop pattern 319 may be selectively removedthrough the slit SI″. Thereafter, the first and second sacrificiallayers 311 and 331 and the sacrificial pad patterns 351 may be removedthrough the slit SI″.

Referring to FIG. 9E, regions from which the first etch stop pattern303, the second portion 319B of the second etch stop pattern 319, thefirst and second sacrificial layers 311 and 331, and the sacrificial padpatterns 351 are removed may be filled with the conductive patterns CP.Thereafter, the sidewall insulating layer SWI, the source contactstructure SC, and the contact plugs CT may be formed using the processesdescribed with reference to FIG. 8E.

The manufacturing method of a semiconductor device according to anembodiment of the present disclosure may be used for forming the memorystring shown in FIGS. 3A to 3D.

According to embodiments of the present disclosure, a level ofdifficulty of the etching process for forming the hole and the slit byusing the etch stop pattern may be decreased.

According to embodiments of the present disclosure, a level ofdifficulty of the process for forming the pad portion of the conductivepattern so that the pad portion may have a great thickness (e.g., agreater thickness than the line portion) by using the etch stop patternmay be decreased.

Since the etch stop pattern according to embodiments of the presentdisclosure includes a material having a significantly different etchrate from the stack structure penetrated by the hole and the slit,widths of the hole and the slit may be uniform.

Since the etch stop pattern according to embodiments of the presentdisclosure is patterned before forming the stepped stack structure, adefect rate of a semiconductor device may be decreased.

FIG. 10 is a block diagram illustrating a configuration of a memorysystem 1100 according to an embodiment of the present disclosure.

Referring to FIG. 10, the memory system 1100 according to an embodimentof the present disclosure may include a memory device 1120 and a memorycontroller 1110.

The memory device 1120 may be a multi-chip package formed of a pluralityof flash memory chips.

The memory controller 1110 may be configured to control the memorydevice 1120 and include a Static Random Access Memory (SRAM) 1111, a CPU1112, a host interface 1113, an Error Correction Code (ECC) 1114, and amemory interface 1115. The SRAM 1111 may serve as an operation memory ofthe CPU 1112. The CPU 1112 may perform overall control operations fordata exchange of the memory controller 1110. The host interface 1113 mayinclude a data exchange protocol for a host connected with the memorysystem 1100. The ECC 1114 may detect and correct errors included in thedata read from the memory device 1120. The memory interface 1115 mayperform interfacing with the memory device 1120. In addition, the memorycontroller 1110 may further include a Read Only Memory (ROM) for storingcode data for interfacing with the host.

In an embodiment, the above-described memory system 1100 may be a memorycard or a Solid State Disk (SSD) equipped with the memory device 1120and the memory controller 1110. For example, when the memory system 1100is an SSD, the memory controller 1110 may communicate with an externaldevice (e.g., a host) through one of various interface protocolsincluding a Universal Serial Bus (USB) protocol, a MultiMedia Card (MMC)protocol, a Peripheral Component Interconnection-Express (PCI-E)protocol, a Serial Advanced Technology Attachment (SATA) protocol, aParallel Advanced Technology Attachment (PATA) protocol, a SmallComputer Small Interface (SCSI) protocol, an Enhanced Small DiskInterface (ESDI) protocol, an Integrated Drive Electronics (IDE)protocol, etc.

FIG. 11 is a block diagram illustrating the configuration of a computingsystem 1200 according to an embodiment of the present disclosure.

Referring to FIG. 11, the computing system 1200 according to anembodiment of the present disclosure may include a CPU 1220, a RandomAccess Memory (RAM) 1230, a user interface 1240, a modem 1250, and amemory system 1210 which are electrically coupled to a system bus 1260.In addition, when the computing system 1200 is a mobile device, abattery for supplying an operating voltage to the computing system 1200may be further included, and an application chipset, a camera imageprocessor (CIS), a mobile DRAM, and the like may be further included.

The memory system 1210 may be configured with a memory device 1212 and amemory controller 1211.

The above-described embodiments are provided for the purpose ofconveying an understanding of the technical spirit of the presentdisclosure. The scope of the present disclosure should not be limited tothe above-described embodiments. It will be obvious to those skilled inthe art to which the present disclosure pertains that othermodifications based on the technical spirit of the present disclosuremay be made in addition to the above-described embodiments.

Unless otherwise defined, all terms including technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art to which the present disclosure belongs.Unless otherwise defined in the present disclosure, the terms should notbe construed as being ideal or excessively formal.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: forming a lower structure including a firstregion and a second region; forming a first etch stop pattern on thelower structure, wherein the first etch stop pattern exposes the secondregion; stacking a plurality of stack structures on the lower structureto overlap the second region and the first etch stop pattern; forming astepped stack structure by etching the plurality of stack structures,wherein the stepped stack structure exposes an end portion of the firstetch stop pattern; forming a slit passing through the stepped stackstructure and the first etch stop pattern; and replacing sacrificiallayers of the plurality of stack structures and the first etch stoppattern with conductive patterns through the slit.
 2. The method ofclaim 1, wherein forming the stepped stack structure by etching theplurality of the stack structures includes exposing the second region.3. The method of claim 1, wherein each of the plurality of stackstructures includes the sacrificial layers and interlayer insulatinglayers alternately stacked, and wherein the first etch stop patternincludes a material having a different etch rate from the sacrificiallayers and the interlayer insulating layers.
 4. The method of claim 3,wherein the sacrificial layers include nitride layers, wherein theinterlayer insulating layers include oxide layers, and wherein the firstetch stop pattern includes metal.
 5. The method of claim 3, wherein thesacrificial layers include nitride layers, wherein the interlayerinsulating layers include oxide layers, and wherein the first etch stoppattern includes a titanium (Ti) compound.
 6. The method of claim 3,wherein the sacrificial layers include nitride layers, wherein theinterlayer insulating layers include oxide layers, and wherein the firstetch stop pattern includes a titanium nitride (TiN) layer.
 7. The methodof claim 1, wherein the stacking of the plurality of stack structurescomprises: forming a first stack structure extending to overlap thefirst etch stop pattern and the second region; forming a first holepassing through the first stack structure; forming a sacrificial pillarfilling the first hole; forming a second stack structure on the firststack structure to cover the sacrificial pillar; forming a second holepassing through the second stack structure and exposing the sacrificialpillar; removing the sacrificial pillar through the second hole to openthe first hole; and forming a channel layer in a channel hole defined bycoupling the first hole and the second hole.
 8. The method of claim 7,wherein the forming of the sacrificial pillar comprises: forming aprotective oxide layer on a surface of the first hole; forming a metallayer filling a portion of the first hole on the protective oxide layer;and forming a second etch stop pattern filling an upper portion of thefirst hole on the metal layer.
 9. The method of claim 1, wherein thestepped stack structure includes a stepped end portion formed of endportions of the sacrificial layers and exposes the end portion of thefirst etch stop pattern, wherein the method further comprises formingsacrificial pad patterns on the end portion of the first etch stoppattern exposed by the stepped end portion and on the end portions ofthe sacrificial layers, and wherein the sacrificial pad patterns arereplaced with the conductive patterns.
 10. The method of claim 9,wherein the replacing of the sacrificial layers and the first etch stoppattern with the conductive patterns comprises: selectively removing thefirst etch stop pattern through the slit; selectively removing thesacrificial layers and the sacrificial pad patterns through the slit;and filling regions from which the first etch stop pattern, thesacrificial layers, and the sacrificial pad patterns are removed with aconductive material.
 11. A method of manufacturing a semiconductordevice, the method comprising: forming a lower structure including afirst region and a second region; forming a first etch stop pattern onthe lower structure, wherein the first etch stop pattern exposes thesecond region; forming a first stack structure on the lower structure tooverlap the second region and the first etch stop pattern; forming asecond etch stop pattern on the first stack structure to expose thesecond region; forming a second stack structure on the second etch stoppattern, the second stack structure overlapping the first region andextending over the second region to overlap the second region; forming astepped stack structure by etching the second stack structure, thesecond etch stop pattern, and the first stack structure, wherein thestepped stack structure exposes an end portion of the first etch stoppattern; forming a slit passing through the stepped stack structure andthe first etch stop pattern; and replacing sacrificial layers of each ofthe first and second stack structures, the first etch stop pattern, andthe second etch stop pattern with conductive patterns through the slit.12. The method of claim 11, wherein forming the stepped stack structureby etching the second stack structure, the second etch stop pattern, andthe first stack structure includes exposing the second region.
 13. Themethod of claim 11, wherein each of the first stack structure and thesecond stack structure includes the sacrificial layers and interlayerinsulating layers alternately stacked, and wherein each of the first andsecond etch stop patterns includes a material having a different etchrate from the sacrificial layers and the interlayer insulating layers.14. The method of claim 13, wherein the sacrificial layers includenitride layers, wherein the interlayer insulating layers include oxidelayers, and wherein each of the first and second etch stop patternsincludes metal.
 15. The method of claim 13, wherein the sacrificiallayers include nitride layers, wherein the interlayer insulating layersinclude oxide layers, and wherein each of the first and second etch stoppatterns includes a titanium (Ti) compound.
 16. The method of claim 13,wherein the sacrificial layers include nitride layers, wherein theinterlayer insulating layers include oxide layers, and wherein each ofthe first and second etch stop patterns includes a titanium nitride(TiN) layer.
 17. The method of claim 11, further comprising: forming afirst hole passing through the first stack structure; forming aprotective oxide layer on a surface of the first hole; forming a metallayer filling a portion of the first hole on the protective oxide layerbefore forming the second etch stop pattern; forming a second holealigned on the first hole by etching the second stack structure and thesecond etch stop pattern; removing the metal layer and the protectiveoxide layer through the second hole so as to open the first hole; andforming a channel layer in a channel hole defined by coupling the firsthole and the second hole.
 18. The method of claim 17, wherein the secondetch stop pattern is formed to fill an upper portion of the first holeon the metal layer.
 19. The method of claim 11, wherein the steppedstack structure includes a stepped end portion formed of end portions ofthe sacrificial layers of each of the first and second stack structuresand an end portion of the second etch stop pattern, the stepped endportion exposing the end portion of the first etch stop pattern, whereinthe method further comprises forming sacrificial pad patterns on the endportion of the first etch stop pattern exposed by the stepped stackstructure, the end portions of the sacrificial layers, and the endportion of the second etch stop pattern, and wherein the sacrificial padpatterns are replaced with the conductive patterns.
 20. The method ofclaim 19, wherein the replacing of the sacrificial layers and the firstand second etch stop patterns with the conductive patterns comprises:selectively removing the first and second etch stop patterns through theslit; selectively removing the sacrificial layers and the sacrificialpad patterns through the slit; and filling regions from which the firstand second etch stop patterns, the sacrificial layers, and thesacrificial pad patterns are removed with a conductive material.